OPERATING SYSTEM (MODULE #2)

OPERATING SYSTEM (MODULE #2)

Introduction to Operating System

(Types of OS & Features)

What is an Operating System?

An Operating system (OS) is a software which acts as an interface between the end user and computer hardware. Every computer must have at least one OS to run other programs. An application like Chrome, MS Word, Games, etc needs some environment in which it will run and perform its task. The OS helps you to communicate with the computer without knowing how to speak the computer's language. It is not possible for the user to use any computer or mobile device without having an operating system.

Operating System with Market Share

• Windows - 40.34

• Android - 37.95

• iOS - 15.44

• Mac OS - 4.34

• Linux - 0.95

• Chrome OS - 0.14

• Windows Phone OS - 0.06

History Of Operating System

• Operating systems were first developed in the late 1950s to manage tape storage

• The General Motors Research Lab implemented the first OS in the early 1950s for their IBM 701 which is the GM-NAA I/O

• In the mid-1960s, operating systems started to use disks

• In the late 1960s, the first version of the Unix OS was developed

• The first OS built by Microsoft was DOS. It was built in 1981 by purchasing the 86-DOS software from a Seattle company

• The present-day popular OS Windows first came to existence in 1985 when a GUI was created and paired with MS-DOS.

Features of Operating System

• Here is a list commonly found important features of an Operating System:

• Protected and supervisor mode

• Allows disk access and file systems Device drivers Networking Security

• Program Execution

• Memory management Virtual Memory Multitasking

• Handling I/O operations

Features of Operating System (Continuation)

• Manipulation of the file system

• Error Detection and handling

• Resource allocation

• Information and Resource Protection

What is a Kernel?

The kernel is the central component of a computer operating systems. The only job performed by the kernel is to the manage the communication between the software and the hardware. A Kernel is at the nucleus of a computer. It makes the communication between the hardware and software possible. While the Kernel is the innermost part of an operating system, a shell is the outermost one.

Features of Kernel

• Low-level scheduling of processes

• Inter-process communication

• Process synchronization

• Context switching

Types of Kernels

There are many types of kernels that exists, but among them, the two most popular kernels are:

Monolithic

A monolithic kernel is a single code or block of the program. It provides all the required services offered by the operating system. It is a simplistic design which creates a distinct communication layer between the hardware and software.

Microkernels

Microkernel manages all system resources. In this type of kernel, services are implemented in different address space. The user services are stored in user address space, and kernel services are stored under kernel address space. So, it helps to reduce the size of both the kernel and operating system.

In an operating system software performs each of the function:

• Memory Management: Memory management module performs the task of allocation and de-allocation of memory space to programs in need of this resources.

• Process Management: Process management helps OS to create and delete processes. It also provides mechanisms for synchronization and communication among processes.

In an operating system software performs each of the function: (cont.,)

• File Management: It manages all the file-related activities such as organization storage, retrieval, naming, sharing, and protection of files.

• Device Management: Device management keeps tracks of all devices. This module also responsible for this task is known as the I/O controller. It also performs the task of allocation and de-allocation of the devices.

In an operating system software performs each of the function: (cont.,)

• I/O System Management: One of the main objects of any OS is to hide the peculiarities of that hardware devices from the user.

• Secondary-Storage Management: Systems have several levels of storage which includes primary storage, secondary storage, and cache storage. Instructions and data must be stored in primary storage or cache so that a running program can reference it.

In an operating system software performs each of the function: (cont.,)

• Security: Security module protects the data and information of a computer system against malware threat and authorized access.

• Command Interpretation: This module is interpreting commands given by the and acting system resources to process that commands.

In an operating system software performs each of the function: (cont.,)

• Networking: A distributed system is a group of processors which do not share memory, hardware devices, or a clock. The processors communicate with one another through the network.

• Job Accounting: Keeping track of time & resource used by various job and users.

• Communication Management: Coordination and assignment of compilers, interpreters, and another software resource of the various users of the computer systems.

Types of Operating system

• Batch Operating System

• Multitasking/Time Sharing OS

• Multiprocessing OS

• Real Time OS

• Distributed OS

• Network OS

• Mobile OS

Batch Operating System

• Some computer processes are very lengthy and time-consuming. To speed the same process, a job with a similar type of needs are batched together and run as a group.

• The user of a batch operating system never directly interacts with the computer. In this type of OS, every user prepares his or her job on an offline device like a punch card and submit it to the computer operator.

Multi-Tasking/Time-sharing Operating Systems

• Time-sharing operating system enables people located at a different terminal(shell) to use a single computer system at the same time. The processor time (CPU) which is shared among multiple users is termed as time sharing.

Distributed Operating System

• A Distributed Operating Systems use many processors located in different machines to provide very fast computation to its users.

Network Operating System

• Network Operating System runs on a server. It provides the capability to serve and manage data, user, groups, security, application, and other networking functions.

Real time OS

• A real time operating system has a very small time interval to process and respond to inputs. Examples: Military Software Systems, Space Software Systems.

Mobile OS

• Mobile operating systems are those OS which is especially that are designed to power smartphones, tablets, and wearables devices.

• Some most famous mobile operating systems are Android and iOS, but others include BlackBerry, Web, and watchOS.

Advantages of using Operating System

• Allows you to hide details of hardware by creating an abstraction.

• Offers an environment in which a user may execute applications.

• The operating system must make sure that the computer system convenient to use with the help of GUI.

• Operating System acts as an intermediary among applications and the hardware components.

• It provides the computer system resources with easy to use format.

• Acts as an intermediator between all hardware's and software's of the system.

Disadvantages of Operating System

• If any issue occurs in OS, you may lose all the contents which have been stored in your system.

• Operating system's software is quite expensive for small size organization which adds burden on them. Example Windows.

• It is never entirely secure as a threat can occur at any time.

Summary

• An operating system is a software which acts as an interface between the end user and computer hardware

• Operating systems were first developed in the late 1950s to manage tape storage

• The kernel is the central component of a computer operating systems. The only job performed by the kernel is to the manage the communication between the software and the hardware.

Summary (continuation)

• Two most popular kernels are Monolithic and MicroKernels.

• Process, Device, File, I/O, Secondary-Storage, Memory management are various functions of an Operating System

• Batch, Multitasking/Time Sharing, Multiprocessing, Real Time, Distributed, Network, Mobile are various types of Operating Systems